Shock absorbing steering column device for vehicle

ABSTRACT

An impact absorption type steering column apparatus for a vehicle includes a car body securing bracket taking substantially an L-shape as viewed from its side. The car body securing bracket is constructed so that a bent portion and a couple of plate-shaped support wall portions are disposed at the rear side of the vehicle on the car body securing portion, and a couple of column fastening fixation portions are disposed at the front side of the vehicle on these plate-shaped support wall portions. With this layout, when a secondary collision happens, the support wall portions of the car body securing bracket and the column fastening fixation portions start moving in the direction of their rotating about the bent portion as a fulcrum, however, this direction is substantially the horizontal direction and is substantially coincident with an input direction (substantially the horizontal direction) of a load of impact from a driver. Therefore, the start of motion of the car body securing bracket at the secondary collision can be stabilized. In a state where the fastening lever is fixed in a tilt adjusted position, a portion to be hand-held of the fastening lever is disposed on a more anterior side of the vehicle than the proximal end portion, and, when the secondary collision happens, the fastening lever moves towards the front of the vehicle, whereby the safety against the collision on a knee of a passenger can be further enhanced.

TECHNICAL FIELD

[0001] The present invention relates to an impact absorption typesteering column apparatus for a vehicle.

BACKGROUND ART

[0002] If an automobile collides against other automobile, a building,etc., a driver collides with a steering wheel by its inertia (which willhereinafter be termed a secondary collision in the presentspecification) in some cases. Cars, etc. in recent years widely adopt animpact absorption type steering column apparatus in order to prevent thedriver from being injured in such a case. In the impact absorption typesteering column apparatus, when the driver secondarily collides with thesteering wheel, the steering column separates from a car body togetherwith a steering shaft or the steering column becomes collapsedsimultaneously with the steering shaft, whereby an impact energy isabsorbed on that occasion.

[0003] Some of the impact absorption type steering column apparatusestake an impact energy absorption system that absorbs the impact energyby causing a flexural deformation of a car body securing bracket forsecuring the steering column to the car body.

[0004] Such an example is disclosed in Japanese Patent Publication No.2978788 and Japanese Patent Application Laid-Open Nos. 2000-229577 and10-16796. FIG. 7 shows one example of the conventional impact absorptiontype steering column apparatus. A tilt adjustment type steering column ais so secured to the car body as to be tilt-adjustable through a carbody securing bracket (tilt bracket) b taking substantially an L-shapeas viewed from its side.

[0005] This car body securing bracket b taking substantially the L-shapeas viewed from its side is constructed of a car body securing portion cfor securing to the car body by use of a bolt, etc., a support wallportion e bent substantially in an L-shape through a bent portion d fromthis car body securing portion c, and a column fastening fixationportion g erected from this support wall portion e formed with a tiltadjustment groove f.

[0006] A distance bracket h fixed by welding, etc. to the steeringcolumn a is slidably provided inside the car body securing bracket (thetilt bracket) b, and a fastening bolt i is inserted through the tiltadjustment groove f of the column fastening fixation portion g andthrough the distance bracket h. A fastening lever j fitted to a proximalend portion of this fastening bolt i is swayed towards a driver on therear side of the vehicle, thereby fixing the car body securing bracket bto the distance bracket h by pressing. Then, the fixation bypress-fitting can be canceled by rotating the fastening lever j in theopposite direction.

[0007] In the examples disclosed in the Publications of the prior artand in the conventional example in FIG. 7, the bent portion d and thesupport wall portion e are disposed at the front side of the vehicle onthe car body securing portion c, and the column fastening fixationportion g formed with the tilt adjustment groove f is disposed at therear side of the vehicle on this support wall portion e.

[0008] Accordingly, when a secondary collision happens, a secondaryimpact load acts towards the front from the rear of the vehicle, withthe result that the steering column a is forced to move toward the frontof the vehicle together with the distance bracket h and the fasteningbolt i. On this occasion, the fastening bolt i starts moving, asindicated by an arrowhead (k) in FIG. 7, with the bent portion d servingas a fulcrum, in a direction considerably downwards from the horizontaldirection and subsequently, as indicated by an arrowhead (k) in FIG. 7,rotates about the bent portion d. With this action, the support wallportion e of the car body securing bracket and the column fasteningfixation portion g become collapsed while causing their flexuraldeformations so as to rotate about the bent portion d (fulcrum), therebyabsorbing an energy of the secondary impact.

[0009] In the examples disclosed in the Publications of the prior artand in the conventional example in FIG. 7, however, the bent portion dand the support wall portion e are disposed at the front side of thevehicle on the car body securing portion c, and the tilt adjustmentgroove f and the column fastening fixation portion g are disposed at therear side of the vehicle on this bent portion d and the support wallportion e. Therefore, when the secondary collision happens, thefastening bolt i (the support wall portion e of the car body securingbracket b and the column fastening fixation portion g) starts moving, asindicated by the arrowhead (k) in FIG. 7, in a direction of rotatingabout the bent portion d as a fulcrum, and this direction isconsiderably downward from the horizontal direction.

[0010] On the other hand, the steering column a is secured to the actualcar at a tilt angle of approximately 20 through 24 degrees, however,when the secondary collision happens, the impact load on the driver actssubstantially horizontally towards the front from the rear of thevehicle.

[0011] Accordingly, there is a considerable deviation between the inputdirection (substantially the horizontal direction) of the impact loadand the actual motion starting direction (downward) of the fasteningbolt i (the support wall portion e of the car body securing bracket band the column fastening fixation portion g). As a result, the start ofmotions of the fastening bolt i and the car body securing bracket b arenot necessarily stable.

[0012] Further, in the conventional example shown in FIG. 7, thefastening lever j extends at the rear side of the vehicle in the statewhere the steering column a is fixed in the tilt adjusting position, andhence this fastening lever might, when the support wall portion e of thecar body securing bracket b and the column fastening fixation portion grotate about the bent portion d (fulcrum) upon the secondary collision,fall down, following up these rotations, from an accommodation areawithin the steering column a and might be positioned in the vicinity ofa knee of the driver.

[0013] Japanese Patent Application Laid-Open No. 10-16796 takes acountermeasure against this incident, wherein the apparatus isstructured to prevent the fastening lever from rotating when thesecondary collision happens. This mechanism is, however, complicatedrequiring an increase in the number of parts, with the result that arise in the manufacturing cost is brought about.

DISCLOSURE OF THE INVENTION

[0014] It is an object of the present invention, which was devised undersuch circumstances, to provide an impact absorption type steering columnapparatus for a vehicle that enhances the safety against the secondarycollision.

[0015] To accomplish the above object, according to a first aspect ofthe present invention, in an impact absorption type steering columnapparatus for a vehicle comprising a car body securing bracketintegrally constructed of a car body securing portion, for securing asteering column to a car body, taking substantially an L-shape as viewedfrom its side and secured to the car body, a couple of support wallportions bent through a bent portion from the car body securing portionand extending in a transversal direction of the steering column, and acouple of column fastening fixation portions erected on the support wallportions, there is provided an improvement characterized in that thebent portion and the couple of support wall portions are disposed at therear side of the vehicle on the car body securing portion, and thecouple of column fastening fixation portions are disposed at the frontside of the vehicle on the support wall portions.

[0016] As described above, according to the impact absorption typesteering column apparatus for the vehicle in the first aspect of thepresent invention, the bent portion and the couple of support wallportions are disposed at the rear side of the vehicle on the car bodysecuring portion, and the couple of column fastening fixation portionsare disposed at the front side of the vehicle on the couple of supportwall portions. With this layout, when the secondary collision happens,the support wall portions of the car body securing bracket and thecouple of column fastening fixation portions start moving in thedirection of their rotating about the bent portion as the fulcrum,however, this direction is substantially the horizontal direction and issubstantially coincident with an input direction (substantially thehorizontal direction) of the load of the impact from the driver.Accordingly, the start of motion of the car body securing bracket at thesecondary collision can be stabilized.

[0017] Further, in the impact absorption type steering column apparatusfor the vehicle according to the first aspect of the present invention,preferably the couple of column fastening fixation portions are formedrespectively with tilt adjustment grooves.

[0018] Moreover, the impact absorption type steering column apparatusfor the vehicle according to the first aspect of the present inventionpreferably further comprises a fastening bolt inserted through the tiltadjustment grooves, and a fastening lever, of which a proximal endportion is fitted to the fastening bolt, swayable between a columnfastening position and a column unfastening position, wherein a portionto be hand-held of the fastening lever is disposed at a more anteriorside of the vehicle than the proximal end portion.

[0019] Furthermore, according to a second aspect of the presentinvention, in an impact absorption type steering column apparatus for avehicle comprising a car body securing bracket integrally constructed ofa car body securing portion, for securing a steering column to a carbody, taking substantially an L-shape as viewed from its side andsecured to the car body, a couple of support wall portions bent througha bent portion from the car body securing portion and extending in atransversal direction of the steering column, and a couple of columnfastening fixation portions erected on the support wall portions, afastening bolt inserted through the tilt adjustment grooves, and afastening lever, of which a proximal end portion is fitted to thefastening bolt, swayable between a column fastening position and acolumn unfastening position, there is provided an improvementcharacterized in that a portion to be hand-held of the fastening leveris disposed on a more anterior side of the vehicle than the proximal endportion.

[0020] As described above, according to the impact absorption typesteering column apparatus in the second aspect of the present invention,in a state where the steering column lever is fixed in a tilt adjustingposition, the portion to be hand-held of the fastening lever is disposedon a more anterior side of the vehicle than the proximal end portion,and, when the secondary collision happens, the fastening lever movestowards the front of the vehicle, whereby the safety against thecollision on a knee of a passenger can be further enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a side view of an impact absorption type steering columnapparatus for a vehicle in an embodiment of the present invention;

[0022]FIG. 2 is a plan view of the impact absorption type steeringcolumn apparatus for the vehicle shown in FIG. 1;

[0023]FIG. 3 is a sectional view taken along the line A-A in FIG. 1;

[0024]FIG. 4 is a side view showing a state where the impact absorptiontype steering column apparatus for the vehicle shown in FIG. 1 ismounted in an actual car;

[0025]FIG. 5 is a side view showing a secondary collision in the statewhere the impact absorption type steering column apparatus for thevehicle is mounted in the actual car;

[0026]FIG. 6 is a side view of the impact absorption type steeringcolumn apparatus for the vehicle in another embodiment of the presentinvention; and

[0027]FIG. 7 is a side view showing a state where an impact absorptiontype steering column apparatus for a vehicle in the prior art is mountedin an actual car.

EMBODIMENTS OF THE INVENTION

[0028] An impact absorption type steering column apparatus for a vehiclein an embodiment of the present invention will hereinafter be describedwith reference to the drawings.

[0029]FIG. 1 is a side view of the impact absorption type steeringcolumn apparatus for the vehicle according to the embodiment of thepresent invention. FIG. 2 is a plan view of the impact absorption typesteering column apparatus for the vehicle shown in FIG. 1. FIG. 3 is asectional view taken along the line A-A in FIG. 1. FIG. 4 is a side viewshowing a state where the impact absorption type steering columnapparatus for the vehicle is mounted in an actual car. FIG. 5 is a sideview showing the state where the impact absorption type steering columnapparatus for the vehicle is mounted in the actual car, and also showinga state of the secondary collision. FIG. 6 is a side view of the impactabsorption type steering column apparatus for the vehicle in anotherembodiment of the present invention.

[0030] As shown in FIG. 1, a steering shaft 2 is rotatably supportedwithin a steering column 1 to which a steering wheel (that is not shownin FIGS. 1 and 2) is fixed on the right side end in FIG. 1. Thissteering column 1 is secured to a car body through a lower bracket 3 atits lower end portion and a car body securing bracket 4 (a tilt bracket)taking substantially an L-shape as viewed from its side at its middleportion.

[0031] The lower bracket 3 is formed with a cut-away portion opened tothe front of the vehicle, and a tilt center bolt 7 fitted to the bracket6 of the steering column 1 is engaged with this cut-away portion 5. Withthis contrivance, when the secondary collision happens, the steeringcolumn 1 becomes movable towards the front of the vehicle.

[0032] The car body securing bracket 4 taking substantially the L-shapeas viewed from its side is constructed integrally of a car body securingportion 10 for securing to the car body through a bolt, etc. extendingin the horizontal direction in FIG. 3, a couple of plate-shaped supportwall portions 12, 12 bent substantially in the L-shape as viewed fromthe side through a bent portion 11 from this car body securing portion10 and extending in the transversal direction of the steering column 1,and a couple of plate-shaped column fastening fixation portions 14, 14erected from the couple of plate-shaped support wall portions 12, 12 andextending in the axial directions on both sides of the steering column1. These column fastening fixation portions 14, 14 are formedrespectively with tilt adjustment grooves 13, 13 for adjusting thesteering column in a tilt adjusting position.

[0033] A distance bracket 15 fixed by welding, etc. to the steeringcolumn 1 is provided in a way that brings both of side end surfaces ofthis bracket 15 into contact with the insides of the couple of columnfastening fixation portions 14, 14 of the car body securing bracket (thetilt bracket) 4. A fastening bolt 16 is inserted through the couple oftilt adjustment grooves 13, 13 of the couple of column fasteningfixation portions 14, 14 and through the both side end surfaces of thedistance bracket 15. A fastening lever 17 is secured to a proximal endportion of this fastening bolt 16.

[0034] As shown in FIG. 3, the proximal end portion of the fasteningbolt 16 is provided with a cam lock mechanism provided with a first cam18 rotating with the fastening lever 17 and a non-rotatable second cam19 engaging with and thus locked to the first cam 18.

[0035] With this configuration, the fastening lever 17 is swayablebetween a fastening position and a unfastening position, and, whenrotated to the fastening position, the steering column 1 is fixed to thetilt adjusted position in a way that fixedly abuts the two side endsurfaces of the distance bracket 15 by pressing through the couple ofcolumn fastening fixation portions 14, 14 of the car body securingbracket 4 by dint of a function of the cam lock mechanism. On the otherhand, when the fastening lever 17 is rotated to the unfasteningposition, the distance bracket 15 is unfastened, whereby the steeringcolumn comes into a tilt position adjustable state.

[0036] According to this embodiment, the fastening lever 17 isconstructed so that when the fastening lever 17 is in a state of beingfixed to the tilt adjusted position, a portion to be hand-held of thefastening lever 17 is disposed on the more anterior side of the vehiclethan the proximal end portion 17 a thereof.

[0037] According to this embodiment, as illustrated in FIGS. 2 and 3,the bent portion 11 of the car body securing bracket 4 is formed with areinforcing bead 11 a, wherein a bending load occurred when the secondcollision happens can be adjusted by changing a size of this reinforcingbead 11 a.

[0038] As shown in FIG. 4, in the state where the impact absorption typesteering column apparatus for the vehicle in this embodiment is mountedin the actual car, the bent portion 11 and the couple of plate-shapedsupport wall portions 12, 12 are disposed at the rear side of thevehicle on the car body securing portion 10 of the car body securingbracket 4, and the couple of column fastening fixation portions 14, 14are disposed at the font side of the vehicle on the plate-shaped supportwall portions 12, 12. The fastening bolt 16 is thereby positioned belowthe bent portion 11 substantially in the vertical direction.

[0039] With the configuration described above, when the load of thesecondary collision acts forwards on the steering wheel 20 from the rearside of the vehicle upon the occurrence of the secondary collision, thesteering column 1 is forced to move forwardly of the vehicle togetherwith the distance bracket 15 and the fastening bolt 16.

[0040] On this occasion, the impact load on the driver actssubstantially horizontally towards the front side from the rear side ofthe vehicle. On the other hand, the fastening bolt 16 is disposed belowthe bent portion 11 substantially in the vertical direction. Thefastening bolt 16 starts moving, as indicated by an arrowhead (x) inFIG. 4, substantially in the horizontal direction with the bent portion11 used as a fulcrum, and subsequently rotates about the bent portion 11(fulcrum) as indicated by an arrowhead (y).

[0041] With this action, as shown in FIG. 5, the impact absorption typesteering column apparatus for the vehicle in this embodiment getscollapsed while causing its flexural deformation in such a way that thecouple of plate-shaped support wall portions 12, 12 of the car bodysecuring bracket 4 and the couple of column fastening fixation portions14, 14 rotate about the bent portion (fulcrum) 11, thereby absorbing anenergy of the secondary impact.

[0042] Thus, according to this embodiment, the bent portion 11 and thecouple of plate-shaped support wall portions 12, 12 are disposed at therear side of the vehicle on the car body securing portion 10, and thecouple of column fastening fixation portions 14, 14 are disposed at thefront side of the vehicle on these plate-shaped support wall portions12, 12. With this layout, when the secondary collision happens, thecouple of plate-shaped support wall portions 12, 12 of the car bodysecuring bracket 4 and the couple of column fastening fixation portions14, 14, start moving in the direction of their rotating about the bentportion 11 serving as the fulcrum, however, this direction issubstantially the horizontal direction and is substantially coincidentwith an input direction (substantially the horizontal direction) of theload of the impact from the driver. Accordingly, the start of motion ofthe car body securing bracket 4 at the secondary collision can bestabilized.

[0043] Further, according to this embodiment, in the state where thefastening lever 17 is fixed in the tilt adjusted position, the portionto be hand-held 17 b of the fastening lever 17 is disposed at a moreanterior side of the vehicle than the proximal end portion 17 a thereof.Besides, when the secondary collision happens, as shown in FIG. 5, thefastening lever 17, following up the collapse of the car body securingbracket 4, moves towards the front of the vehicle while rotating,whereby the safety against the collision on the knee of a passenger canbe further enhanced.

[0044]FIG. 6 shows a side view of the impact absorption type steeringcolumn apparatus for the vehicle in still another embodiment of thepresent invention. A different point of this embodiment from theembodiment discussed above lies in a structure of the car body securingbracket. In this embodiment, a bent portion 111 and a couple ofplate-shaped support wall portions 112, 112 are disposed at the frontside of the vehicle on a car body securing portion 110 of a car bodysecuring bracket 104. A couple of column fastening fixation portions114, 114 are disposed at the rear side of the vehicle on theplate-shaped support wall portions 112, 112 and are formed respectivelywith tilt adjustment grooves 113, 113. Other constructions are the sameas those-in the embodiment discussed above and marked with the samesymbols, and their explanations are omitted.

[0045] The apparatus being configured described above, when thesecondary collision happens, the secondary impact load acts toward thefront from the rear of the vehicle, with the result that the steeringcolumn 1 is forced to move on the front side of the vehicle togetherwith a distance bracket 15 and a fastening bolt 16. On this occasion,the fastening bolt 16 starts moving, with the bent portion 111 servingas a fulcrum, in a direction considerably downwards from the horizontaldirection and rotates about the bent portion (fulcrum) 111. With thisaction, the impact absorption type steering column apparatus getscollapsed while causing its flexural deformation in such a way that thecouple of plate-shaped support wall portions 112, 112 of the car bodysecuring bracket 104 and the couple of column fastening fixationportions 114, 114 rotate about the bent portion (fulcrum) 111, therebyabsorbing an energy of the secondary impact.

[0046] Further, also in this embodiment, in the state where thefastening lever 17 is fixed in the tilt adjusted position, the portionto be hand-held 17 b of the fastening lever 17 is disposed at the moreanterior side of the vehicle than the proximal end portion 17 a thereof,and, besides, when the secondary collision happens, the fastening lever17, following up the collapse of the car body securing bracket 104,moves towards the front of the vehicle while rotating, whereby thesafety against the collision on the knee of the passenger can be furtherenhanced.

[0047] Note that the present invention is not limited to the embodimentsdiscussed above and can be modified in many ways. For example, in theembodiments discussed above, the present invention is applied to the carbody securing bracket (the tilt bracket) and may also be applied to thelower bracket.

[0048] As described above, according to the present invention, it ispossible to provide the impact absorption type steering column apparatusfor the vehicle that further enhances the safety against the secondarycollision.

What is claimed is:
 1. In an impact absorption type steering columnapparatus for a vehicle, comprising: a car body securing bracketintegrally constructed of a car body securing portion, for securing asteering column to a car body, taking substantially an L-shape as viewedfrom its side and secured to the car body, a couple of support wallportions bent through a bent portion from said car body securing portionand extending in a transversal direction of said steering column, and acouple of column fastening fixation portions erected on said supportwall portions, an improvement characterized in that said bent portionand said couple of support wall portions are disposed at the rear sideof the vehicle on said car body securing portion, and said couple ofcolumn fastening fixation portions are disposed at the front side of thevehicle on said support wall portions.
 2. An impact absorption typesteering column apparatus for a vehicle according to claim 1, whereinsaid couple of column fastening fixation portions are formedrespectively with tilt adjustment grooves.
 3. An impact absorption typesteering column apparatus for a vehicle according to claim 1 or 2,further comprising a fastening bolt inserted through said tiltadjustment grooves, and a fastening lever, of which a proximal endportion is fitted to said fastening bolt, swayable between a columnfastening position and a column unfastening position, wherein a portionto be hand-held of said fastening lever is disposed at a more anteriorside of the vehicle than the proximal end portion.
 4. In an impactabsorption type steering column apparatus for a vehicle, comprising: acar body securing bracket integrally constructed of a car body securingportion, for securing a steering column to a car body, takingsubstantially an L-shape as viewed from its side and secured to the carbody, a couple of support wall portions bent through a bent portion fromsaid car body securing portion and extending in a transversal directionof said steering column, and a couple of column fastening fixationportions erected on said support wall portions; a fastening boltinserted through said tilt adjustment grooves; and a fastening lever, ofwhich a proximal end portion is fitted to said fastening bolt, swayablebetween a column fastening position and a column unfastening position,an improvement characterized in that a portion to be hand-held of saidfastening lever is disposed at a more anterior side of the vehicle thanthe proximal end portion.